Improvement in dies for raising articles of sheet metal



N. C. STI L ES. Dies for Raising Articles of She et-Metal.

Patented March-30,1875.

PATENT IFFTGE.

NORMAN C. STILES, OF MIDDLETOWN, CONNECTICUT.

IMPROVEMENT IN DIES FOR RAISING ARTICLES OF SHEET METAL.

Specification forming part of Letters Patent No. 161,572, dated arch 30,1875; application filed February 18, 1875.

To all whom it may concern:

Be it known that I, NORMAN C. STILEs, of Middletown, in the county ofMiddlesex and State of Connecticut, have invented a new Improvement inDies for Striking Articles from Sheet Metal; and I do hereby declare thefollowing, when taken in connection with the accompanying drawings andthe letters of reference marked thereon, to be a full, clear, and exactdescription of the same, and which said drawings constitute part of thisspecification, and represent a vertical central section of the die andfollower.

This invention relates to an improvement in dies, such as used forstriking or drawing up articles from sheetmetal blanks.

In the usual method of doing this class of work a double-action press isemployed-one follower or punch, A, within another, B. The outer followerB bears upon the surface of the metal blank, while the punch A forcesthe central part of the blank down into or through.

the die, gradually drawing it from beneath the outside follower orholder B, so as to prevent Jhe wrinkling of the metal at tl-re'edges. In

somecases the o'utside follower is a punch to cut the blank from thesheet, and there hold it, as before described.

In this operation of drawing it is essential that the blank be heldalike, or with equal pressure at all points around its edge. This isfound difficult to do, as there will be slight variations in thethickness of the blank.

To overcome this difficulty is the object of my invention; and itconsists in making the drawing part of the die self adjusting relativeto the face or plane of the external follower or punch.

concave, as seen in the drawing. The interior of the part D is of theform of the exterior of the thing to be drawn. Over or above this is thecutting-die E, or, may be, a guide, corresponding substantially to theexternal follower or punch B, the punch A less in dimension than the.part D of the die-that is, corresponding to the interior of the thing tobe drawnsubstantiall y as in the usual construction.

A slight play is allowed to the part D, so that, if the pressure begreater at one point than at another, the said part D will be depressedat that point, and raised at the opposite point; hence, if the blank tobe struck is slightly thicker at one point than at the opposite, thefollower B will force the part D to turn or tip until the pressure isalike at all points. The variation is so slight that it will notmaterially change the relative positions of the punch A and the part D.

While I prefer the spherical form for the part D, any form orarrangement which will allow a universal self-adjustment relative to theplane of the follower B will accomplish the same result. I therefore donot confine myself to the said spherical form.

I have described the part D as of the die; but it will be evident thatit may be in like manner attached to the follower with precisely thesame result.

I claim In combination with a central punch, A, and external follower orpunch B, the part D, arranged substantially as described, so as to beuniversally self adjusting relatively to the plane of the follower B,substantially as specilied.

NORMAN C. STILES.

Witnesses:

S. A. RoBINsoN, VICTOR A. KING.

